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本文研究n体聚集过程和联合聚集过程的集团分布演化。从广义Smoluchovki方程出发,给出聚集核K(i1,i2,…,in)=A sumfrom i=1 to n i1+B(A,B均为常数)的显解;利用聚集核K(i1,i2,…,in)=(Ai1+B)(Ai2+B)…(Ain+B)和核K(i1,i2,…,in)=A sumfrom i=1 to n i1+B的方程之间的联系,得出核K(i1,i2,…,in)=S(i1)S(i2)…S(in)(SK=AK+B)的凝前解。而且,根据联合聚集动力学方程,讨论了聚集和型核分别为K2(i,j)=i+j,K3(i,j,k)=i+j+k的集团尺寸分布Cm(t)的长时行为,并将结论推广到一般的联合聚集过程。
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本文对用Co2+-Ti4+和Cu2+-Nb5+离子取代BaFe12O19单晶体中Fe3+离子进行了研究,以Bi2O3作为助熔剂生长出了BaFe12-2xCox2+Tix4+O19(x=0;0.04;0.09;0.13;0.27和0.68)以及BaFe12-x[Nb1/35+Cu2/32+]xO19(x=0;0.28;0.44和0.60)这两系列的单晶体,测定了100—300K温度范围内样品的磁化强度σ与单轴各向异性常数K1,我们发现,对Co2+-Ti4+取代的样品,当x≤0.09时,其σ与K1随x的增加而缓慢增加;当x>0.09时,其σ与K1随x的增加而迅速降低,至x=1.1时,K1变为零,对Nb5+-Cu2+取代的样品,其σ值在整个成份范围内基本保持不变,且有缓慢增加趋势;而K1值则随x增加而单调下降,提出了取代离子在M型六角铁氧体中可能的分布模型来解释我们的结果。
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本文利用反应显微成像技术(reaction microscope)研究了54 eV电子入射甲烷分子导致的电离解离过程,详细分析了电离解离产生的CH+2,CH+,C+离子碎片的动能分布情况.实验结果表明,该入射能量下产生CH+2,CH+,C+离子碎片主要贡献来自2a1内价轨道电子的直接电离过程产生的离子态(2a<
关键词:
反应显微成像谱仪
电离解离
能量沉积
动能分布 相似文献
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采用高温固相法,通过阳离子替代的实验策略,制备出系列窄带发射且颜色可由深黄色调至绿色的K2-xNaxZn0.94SiO4∶0.06Mn2+(0≤x≤2)荧光粉。用X射线粉末衍射仪对样品的物相进行表征,通过扫描电子显微镜和能量色散谱测试对样品的形貌和元素分布进行分析。结果表明,成功地合成了纯相且元素分布均匀的K2-xNaxZn0.94SiO4∶0.06Mn2+(0≤x≤2)荧光粉。在蓝光激发下,随着Na+离子逐渐代替K+离子,K2-xNaxZn0.94SiO4∶0.06Mn2+(0≤x≤2)荧光粉的发光强度逐渐增强,原荧光粉的发光强度得到有效提高的同时发光颜色由深黄色调至绿色。在427 nm激光的激发下:当x=0.8时,... 相似文献
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本文应用动力学方法计算了均匀非磁化等离子体的电子二级非线性密度涨落,得到了三波在等离子体中相互作用的三级非线性极化率X(3)和第四波K4=K1-K2+K3,ω4=ω1-ω2+ω3的散射功率,与通常的非相干汤姆逊散射相比,其散射信号要大得多,因此,相干四光子散射可以作为等离子体诊断技术的一个重要方法,本文还指出,文献[4]的结果是本文计算的一个简单情况。
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The critical behavior of the gelation of polymers is studied by means of the generalized Srnoluchovski's coagulation equation. The exact solution of the kinetic equation with a factorial coagulation rate R(i1, i2, . . . in) = si1 × si2 × . . . × sin and sk = A × k + B is derived for the monodisperse initial condition cm(O) = δm, 1. It is shown that a gelation transition takes place within a finite time tc and the gelation time tc ii characterized by the parameters A and B. 相似文献
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本文引入并论证了描述动态位错场的张量势(A与B)的规范交换问题,而且证明这种变换可采取这样的形式:B′=B+▽F, A′=A-ρ?/(?t)▽G,x′=x-ρ?/(?t)F,其中xi=eiklAkl。至于F与G,则为带有很大任意性的时空坐标的矢量函数,但它们要满足以下关系式:F=▽×G,▽2F-1/Gt2-(?2/?t2)F=0.进
关键词: 相似文献
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ZHUJian-Yang YANGZhan-Ru 《理论物理通讯》2001,35(4):469-474
A single-spin transition critical dynamics is used to investigate the three-dimensional kinetic Ising model on an anisotropic cubic lattice,We first derive the fundamental dynamical equations.and then linearize them by a cutoff approximation.We obtain the approximate solutions of the local magnetization and equal-time pair correlation function approximation.We obtain the approximate solutions of the local magnetization and equal-time pair correlation function in zero field.In which the axial-decoupling terms γ1γ2,γ2γ3and γ1γ3as higher infinitesimal quantity are ignored,where γα=tanh(2k0633)=tanh(2Jα/kβT)(α=1,2,3,)We think that it is reasonable as the temperature of the system is very high.The result of what we obtain in this paper can go back to the one-dimensional Glauber‘s theory as long as k2=k3=0. 相似文献
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Chuan Sheng Liu Tripathi V.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(2):353-358
A laser incident on a metal film (deposited on a glass substrate) from the glass side at a specific angle of incidence, excites a surface plasma wave (SPW) at the metal-free space interface. The ratio of the SPW field to the laser field increases with the laser spot size b attaining a value much greater than one at b>exp(2wα/c) where a is the film thickness and ω is the laser frequency. The SPW (ω, kz,) can also he excited by a relativistic electron beam, propagating parallel to the interface in the free space region, via Cerenkov interaction when beam energy ϵb=(|ϵ|-1)mc2 where ϵ is the effective metal permittivity, and mc2 is the electron rest mass energy. When the surface has a ripple of wave number k0, the SPW (ω, kzz) can be excited at lower beam energy via sideband coupling, ω=(kzz +k0)vb where vbzˆ is the beam velocity. In both cases, however, the positioning of the beam in the close proximity of the interface is required. The scheme is useful for the generation of wavelengths longer than 1 μm 相似文献
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Our analyais[1] has shown that there exist sensitive and insensitive regions to determine the spin (J = 2 or 4) of ξ(2230) in the general helicity formalism. Whereaa it just falls into the insensitive region by using current data of ξ. If the number of events is not sufficient it is difficult to determine the spin of ξ[2]. In this paper we generalize the moment analysis[3]. We define the photon angular distribution HJ(θτ, LM) for the moment of process e+ +R- → J/ψ → τ + ξ, ξ → p + p and the weighted moment by choosing appropriate weight function. They provide an effective criterion to determine the spin of ξ. We also use the method to discuss LIE puzzle for process e+ + e- → J/ψ → τ + B1 B → P1 + P2 + P3. 相似文献
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本文构造了解色散方程u1=auxxx的若干三层恒稳的半显式差分格式。第Ⅰ、Ⅱ类格式的局部截断误差的阶为O(τ2+h2+(τ2)/(h3));而第Ⅲ、Ⅳ类格式的局部截断误差的阶为O(τ2+h4+((τ)/(h))2+τh)。用判别稳定性的Von Neumann准则可证明:第Ⅰ、Ⅱ类格式及当参数α≤1时的第Ⅲ、Ⅳ类格式都是无条件稳定的,并且当必须的边界条件给定时它们可以显式地进行计算。 相似文献
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In this paper, the stability of
disclination ring in nematic liquid crystals is studied. In the
presence of saddle-splay elasticity (characterized by k24)
the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant
k24, the universal equilibrium radius is altered. When
k24>>0.92k (m=1/2) and
k24>>0.88k (m=-1/2), the
disclination will be a point rather than a ring, where $k$ is the
Frank elastic constant in the one-constant approximation. 相似文献
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In this paper the lattice current-current propagator is calcdlated and the influence of coset pure gauge fields of an abelian chiral group G=U1×U15 on confinement properties of a quark system is discussed by virtue of the Wilson's criterion in lattice gauge theory. When subgroup H is U1, the coset pure gauge fields only contribute a perimeter law factor to the current current propagator which has no influence on confinement properties of the system. When subgroup H is Us, the coset puregauge fields have no influence on wnfinement properties of the system either. 相似文献
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高压阻塞喷注的湍流噪声 总被引:6,自引:0,他引:6
过去曾求得驻点压力(表压)在0.01到10大气压适用的喷注噪声的压力关系。现在将实验扩展到100大气压过热水蒸汽,发现低压时的关系仍然适用,不过由于喷注气体不同,此时多一个附加项20log(M0/M),M0和M分别是空气和喷注气体的分子量;喷注温度则几乎无影响。于是,在与喷注方向垂直,距离喷口1米处的A声级就成为${L_A} = 80 + 20\\log \\frac{D}{{{D_0}}} + 20\\log \\frac{{{M_0}}}{M} + 10\\log \\frac{{{{(P - {P_0})}^4}}}{{{P_0}^2{{(P - 0.5{P_0})}^2}}} + 10\\log \\left[ {\\frac{2}{\\pi }\\left( {{{\\tan }^{ - 1}}{x_A} - \\frac{{{x_A}}}{{1 + {x_A}^2}}} \\right)} \\right]$式中D为喷口直径(mm),D0为1mm, P和 P0分别为喷注驻压和环境大气绝对压力,在阻塞时xA=0.165D/D0实验证明在较大的温度和压力范围,噪声频谱无甚差别。管道内的扰动可使噪声级提高1-6dBA,对此本文作了理论分析。低压时使 用的小孔消声器在高压下仍然有效,但应注意其特有的关系. 相似文献